In vitro maturation of human oocytes in a follicle-mimicking three-dimensional coculture

OBJECTIVE: To verify the hypothesis that a three-dimensional, follicle-mimicking structure enhances in vitro maturation yields without hormonal supplementation in an in vitro maturation program. DESIGN: Feasibility study; 204 anonymous denuded germinal vesicles retrieved from gonadotropin-treated women were cultured for 48 hours without hormonal supplementation in microdrop culture or in a three-dimensional coculture with granulosa cells in a barium alginate membrane. SETTING: An assisted reproduction center in Italy. PATIENT(S): One hundred twenty-two informed women. INTERVENTION(S): Germinal vesicles retrieved after ovarian stimulation were denuded and cultured without hormonal supplementation in microdrop culture or in a three-dimensional coculture with granulosa cells enclosed in the core of a barium alginate capsule. MAIN OUTCOME MEASURE(S): Oocyte maturation and morphological investigation of follicle-mimicking structures. RESULT(S): Statistically significantly higher oocyte maturation yields were obtained by using the three-dimensional coculture system enclosed in a barium alginate membrane (after 48 hours: coculture, 90.3%; microdrop, 52.0%; odds ratio, 8.51). Morphological investigation indicated that after 48 hours of coculture, the decumulated oocyte appeared to be surrounded by a pseudocumulus structure that lies on the inner surface of the alginate membrane and protrudes toward the capsule's lumen. CONCLUSION(S): The maturation yield of cocultured oocytes is eightfold higher than that achieved with a microdrop maturation technique, making a higher number of gametes available for IVF programs. Stereomicroscopic morphological survey indicates a reassembly of granulosa cells surrounding oocyte zona, mimicking an antral cumulus oophorus.